Columbia Electrical Contractor Examination
Practice Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
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Question 1
What is the primary purpose of the National Electrical Code (NEC)?
A. To establish electrical utility rates
B. To regulate the price of electrical materials
C. To provide practical safeguards for persons and property from
electrical hazards
D. To establish requirements for electrical contractor licensing in every
jurisdiction
Correct Answer: C. To provide practical safeguards for persons and
property from electrical hazards
Rationale: The NEC is primarily a safety standard intended to protect
people and property from hazards arising from the use of electricity. It
,establishes minimum requirements for electrical installations, while
local jurisdictions may adopt amendments or additional licensing
requirements.
Question 2
Which NEC article contains the general requirements for conductors
and cables?
A. Article 210
B. Article 300
C. Article 430
D. Article 680
Correct Answer: B. Article 300
Rationale: NEC Article 300 establishes general requirements for wiring
methods and materials. Other articles provide additional
requirements for particular applications, but Article 300 supplies many
of the foundational installation rules.
Question 3
,A 120-volt branch circuit supplies a continuous load of 16 amperes.
What minimum ampacity is generally required for the branch-circuit
conductors?
A. 16 A
B. 18 A
C. 20 A
D. 25 A
Correct Answer: C. 20 A
Rationale: A continuous load is generally calculated at 125 percent of
its actual value. Therefore, 16 A × 125% = 20 A. The conductors and
overcurrent protection must be selected to accommodate the
calculated load.
Question 4
What is the minimum rating generally permitted for a standard 15-
ampere branch-circuit overcurrent protective device?
A. 10 A
B. 15 A
C. 20 A
D. 25 A
, Correct Answer: B. 15 A
Rationale: The rating of the overcurrent protective device must be
coordinated with the circuit conductors and equipment. A 15-ampere
branch circuit is normally protected by a 15-ampere overcurrent
device unless a specific NEC provision permits otherwise.
Question 5
Which conductor is normally identified by a continuous green covering
or green with one or more yellow stripes?
A. Ungrounded conductor
B. Grounded conductor
C. Equipment grounding conductor
D. Isolated neutral conductor
Correct Answer: C. Equipment grounding conductor
Rationale: Equipment grounding conductors are generally identified
by green insulation or by green insulation with one or more yellow
stripes. Their purpose is to provide a low-impedance path for fault
current back to the source so that protective devices can operate.
Practice Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
Question 1
What is the primary purpose of the National Electrical Code (NEC)?
A. To establish electrical utility rates
B. To regulate the price of electrical materials
C. To provide practical safeguards for persons and property from
electrical hazards
D. To establish requirements for electrical contractor licensing in every
jurisdiction
Correct Answer: C. To provide practical safeguards for persons and
property from electrical hazards
Rationale: The NEC is primarily a safety standard intended to protect
people and property from hazards arising from the use of electricity. It
,establishes minimum requirements for electrical installations, while
local jurisdictions may adopt amendments or additional licensing
requirements.
Question 2
Which NEC article contains the general requirements for conductors
and cables?
A. Article 210
B. Article 300
C. Article 430
D. Article 680
Correct Answer: B. Article 300
Rationale: NEC Article 300 establishes general requirements for wiring
methods and materials. Other articles provide additional
requirements for particular applications, but Article 300 supplies many
of the foundational installation rules.
Question 3
,A 120-volt branch circuit supplies a continuous load of 16 amperes.
What minimum ampacity is generally required for the branch-circuit
conductors?
A. 16 A
B. 18 A
C. 20 A
D. 25 A
Correct Answer: C. 20 A
Rationale: A continuous load is generally calculated at 125 percent of
its actual value. Therefore, 16 A × 125% = 20 A. The conductors and
overcurrent protection must be selected to accommodate the
calculated load.
Question 4
What is the minimum rating generally permitted for a standard 15-
ampere branch-circuit overcurrent protective device?
A. 10 A
B. 15 A
C. 20 A
D. 25 A
, Correct Answer: B. 15 A
Rationale: The rating of the overcurrent protective device must be
coordinated with the circuit conductors and equipment. A 15-ampere
branch circuit is normally protected by a 15-ampere overcurrent
device unless a specific NEC provision permits otherwise.
Question 5
Which conductor is normally identified by a continuous green covering
or green with one or more yellow stripes?
A. Ungrounded conductor
B. Grounded conductor
C. Equipment grounding conductor
D. Isolated neutral conductor
Correct Answer: C. Equipment grounding conductor
Rationale: Equipment grounding conductors are generally identified
by green insulation or by green insulation with one or more yellow
stripes. Their purpose is to provide a low-impedance path for fault
current back to the source so that protective devices can operate.
